In an image forming apparatus that forms an image electrophotographically, developer is supplied to a charged photosensitive member so as to form a developer image, and the developer image is transferred and fixed to a recording sheet. In such an image forming apparatus, a charger using a corona discharge is often used for charging the photosensitive member.
JP-A-2006-039139 discloses a related charger using a corona discharge. The related charger has a charging wire and a grid electrode. The charging wire is supplied with a voltage that is higher than that applied to the grid electrode. The grid electrode has a metal plate on which an opening area having a plurality of slit-shaped openings is formed. A charged air is flown from the charging wire toward the grid electrode through the opening area.